# US 10,308,575 B2 · Methanol process

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- Number: US 10,308,575 B2
- Document ID: US10308575B2
- Status: Granted
- Kind: B2
- Application number: 16/067,419
- Filed: 2016-12-16
- Published: 2019-01-17
- Granted: 2019-06-04
- Earliest claimed: 2016-01-15
- Assignees: Johnson Matthey Davy Technologies Limited
- Applicants: Johnson Matthey Davy Techhnologies Limited
- Inventors: Kar Chi Yiu
- Web page: https://patentgrep.com/patent/US10308575B2

## CPC

- C07C 29/1516: {Multisteps}
- B01D 3/143: {by two or more of a fractionation, separation or rectification step}
- B01J 23/72: Copper
- C01B 3/506: at low temperatures
- C07C 29/152: characterised by the reactor used
- C07C 29/154: containing copper, silver, gold, or compounds thereof
- C07C 31/04: Methanol
- B01D 2256/16: Hydrogen
- B01D 2257/70: Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
- B01J 2203/06: High pressure synthesis
- B01J 2523/17: Copper
- B01J 2523/27: Zinc
- B01J 2523/31: Aluminium
- C01B 2203/0216: containing a non-catalytic steam reforming step
- C01B 2203/0283: containing a CO-shift step, i.e. a water gas shift step
- C01B 2203/061: Methanol production
- Y02P 20/129: Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
- Y02P 20/52: using catalysts, e.g. selective catalysts
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A process is described for the synthesis of methanol comprising the steps of: (i) passing a first synthesis gas mixture comprising a make-up gas through a first synthesis reactor containing a cooled methanol synthesis catalyst to form a first product gas stream, (ii) recovering methanol from the first product gas stream thereby forming a first methanol-depleted gas mixture, (iii) combining the first methanol-depleted gas mixture with a loop recycle gas stream to form a second synthesis gas mixture, (iv) passing the second synthesis gas mixture through a second synthesis reactor containing a cooled methanol synthesis catalyst to form a second product gas stream, (v) recovering methanol from the second product gas stream thereby forming a second methanol-depleted gas mixture, and (vi) using at least part of the second methanol-depleted gas mixture as the loop recycle gas stream, wherein the first synthesis reactor has a higher heat transfer per cubic meter of catalyst than the second synthesis reactor, none of the loop recycle gas stream is fed to the first synthesis gas mixture and the recycle ratio of the loop recycle gas stream to form the second synthesis gas mixture is in the range 1.1:1 to 6:1.

## Claims

### Claim 1

A process for synthesizing methanol comprising the steps of:
(i) passing a first synthesis gas mixture comprising a make-up gas through a first synthesis reactor containing a first cooled methanol synthesis catalyst to form a first product gas stream,
(ii) recovering methanol from the first product gas stream to form a first methanol-depleted gas mixture,
(iii) combining the first methanol-depleted gas mixture with a loop recycle gas stream to form a second synthesis gas mixture,
(iv) passing the second synthesis gas mixture through a second synthesis reactor containing a second cooled methanol synthesis catalyst to form a second product gas stream,
(v) recovering methanol from the second product gas stream to form a second methanol-depleted gas mixture, and
(vi) using at least part of the second methanol-depleted gas mixture as the loop recycle gas stream,
wherein the first synthesis reactor has a higher heat transfer per cubic meter of catalyst than the second synthesis reactor, none of the loop recycle gas stream is fed to the first synthesis gas mixture and the recycle ratio of the loop recycle gas stream to form the second synthesis gas mixture is in the range of from 1.1:1 to 6:1.

### Claim 2 (depends on 1)

The process according to claim 1 wherein the make-up gas contains carbon monoxide in the range of from 10-20% vol and is passed directly to the first cooled methanol synthesis reactor without diluting with other gases.

### Claim 3 (depends on 1)

The process according to claim 1 wherein the make-up gas contains carbon monoxide in the range of from 20-35% vol and is diluted with a hydrogen-containing gas stream selected from a purge gas stream from another methanol process or a hydrogen gas stream.

### Claim 4 (depends on 1)

The process according to claim 1 wherein a single circulator is used for feeding the combined loop recycle gas and the first methanol depleted gas mixture to the second synthesis reactor.

### Claim 5 (depends on 1)

The process according to claim 1 wherein the recycle ratio of the loop recycle gas stream to form the second synthesis gas mixture is in the range of from 1.5:1 to 6:1.

### Claim 6 (depends on 1)

The process according to claim 1 wherein the first synthesis reactor comprises a first cooled methanol synthesis catalyst disposed in tubes that are cooled by water under pressure, the second synthesis reactor comprises a fixed bed of a second cooled methanol synthesis catalyst that is cooled in heat exchange with either water under pressure or a synthesis gas mixture from the first synthesis gas mixture or the second synthesis gas mixture.

### Claim 7 (depends on 1)

The process according to claim 1 wherein the first synthesis reactor is axial flow steam-raising converter.

### Claim 8 (depends on 1)

The process according to claim 1 wherein the second synthesis reactor is selected from a radial flow steam-raising converter, a tube-cooled converter, a gas-cooled converter or a quench reactor.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the first, second, or first and second cooled methanol synthesis catalyst is a copper-containing methanol synthesis catalyst.

### Claim 10 (depends on 1)

The process according to claim 1 wherein methanol synthesis in the first and second reactors is performed at pressures in the range of from 20 to 120 bar abs and temperatures in the range of from 130° C. to 350° C.

### Claim 11 (depends on 1)

The process according to claim 1 wherein the gas mixtures fed to the first and second synthesis reactors are heated in gas-gas heat exchangers using the product gases from the reactors.

### Claim 12 (depends on 1)

The process according to claim 1 wherein the product gas streams from the first and second synthesis reactors are cooled in one or more stages of heat exchange to condense methanol therefrom.

### Claim 13 (depends on 1)

The process according to claim 1 wherein a purge gas stream is recovered from the second methanol depleted gas mixture and is used for hydrogen recovery, or is subjected to one or more further processing stages including autothermal reforming, water-gas shift, or methanol synthesis.

### Claim 14 (depends on 1)

The process according to claim 1 wherein the recycle ratio of the loop recycle gas stream to form the second synthesis gas mixture is in the range of from 2:1 to 6:1.

### Claim 15 (depends on 1)

The process according to claim 1 wherein the first, second, or first and second cooled methanol synthesis catalyst is a compositions comprising copper, zinc oxide and alumina.

### Claim 16 (depends on 12)

The process according to claim 12, wherein the condensed methanol is recovered and further processed using one or more stages of distillation to produce a purified methanol product.